What is IIH?
Idiopathic intracranial hypertension (IIH) is also called “pseudotumour cerebri” (PTC) or “benign intracranial hypertension (BIH). The most commonly used name is IIH, which means:
- Idiopathic - happens spontaneously for no known reason
- Intracranial - inside the head
- Hypertension - high pressure
So people with IIH have high pressure inside the head for no known reason.
What are the symptoms of IIH?
The most common symptom of IIH is headache. These headaches are different from most other headaches because they usually get worse with lying down. Many people also have vision problems including blurred vision, dim vision, loss of peripheral vision, flashing lights, vision that dims or blacks out with bending over or straining or double vision. Some people hear a whooshing sound in their head in time with their heart beat.
Who gets IIH?
IIH typically affects young, overweight women, although there are always exceptions. IIH may be triggered by a recent weight gain. Sometimes IIH is not actually idiopathic and is caused by certain medications like tetracycline antibiotics, acne medications or steroids.
How is IIH diagnosed?
Most people with IIH have swelling of their optic nerves. Your eye doctor can detect this by dilating your pupils and looking at the back of your eyes. Swollen optic nerves can be caused by many other things and it important that your eye doctor makes sure there is nothing else going on. To do this, your doctor will arrange imaging of your brain, either and MRI or a CT scan. If this is normal, the next step is a spinal tap, both to measure the intracranial pressure and to make sure there is no infection or inflammation in the cerebrospinal fluid which surrounds your brain.
Normal Optic Nerve
Optic disc edema
Swollen optic nerve in patient with IIH.
Mild optic disc edema
Sometimes swelling can be mild and difficult to see.
How is IIH treated?
If you are overweight, the most effective treatment of IIH is usually weight loss. If this is not possible, or more urgent treatment is needed, there are a variety of medical and surgical treatments available.
The most common medication used to treat IIH is called acetazolamide (Diamox).
Most people need to be on the medication for around 1.5 years and then are able to stop.
Surgery is recommended for people who don’t respond to the medication or who have severe symptoms. Surgery may involve placing a tube from your brain into your abdomen to relieve the pressure. Another option is to make an opening in the covering around your optic nerves to reduce the pressure behind your eyes.
Will I go blind?
Most people do very well with treatment and usually have little permanent vision loss. People are more likely to have poor outcomes if they are male or have severe vision loss at the beginning.